What causes earthquakes? Earthquakes occur when stress builds up in zones of weakness in the earth’s crust. These areas are known as faults. The released energy from a broken fault radiates in all directions. The epicenter is the term used for the point directly over the earthquake on the surface. Measuring Earthquakes A Seismologist is a person who studies earthquakes. The scientific tool they use is called a seismograph. During an earthquake, the earth shakes. How much it shakes is called the magnitude.
Earthquake waves • P-waves are also known as primary waves. This is because they travel the fastest. • P-waves are also known as compressional waves which can be thought of as a “push/ pull” movement. • P-waves travel through all materials. • S-waves are also known as secondary waves because they travel slower and ALWAYS arrive after P-waves. • S-waves travel like light waves in that they are “side to side” waves. • S-waves only travel through Solids (S=S).
Locating an epicenter This has to do with figuring out the difference in P-wave and S-wave arrival times. The closer (in minutes and seconds) they are together, the closer you are to the epicenter. Conversely, the farther the time between P-waves and S-waves, the farther you are located away from the epicenter.
Brain Teaser: If they occur at the same exact time, where are you located???
What causes earthquakes?
Earthquakes occur when stress builds up in zones of weakness in the earth’s crust. These areas are known as faults. The released energy from a broken fault radiates in all directions. The epicenter is the term used for the point directly over the earthquake on the surface.
Measuring Earthquakes
A Seismologist is a person who studies earthquakes. The scientific tool they use is called a seismograph. During an earthquake, the earth shakes. How much it shakes is called the magnitude.
Earthquake waves
• P-waves are also known as primary waves. This is because they travel the fastest.
• P-waves are also known as compressional waves which can be thought of as a “push/ pull” movement.
• P-waves travel through all materials.
• S-waves are also known as secondary waves because they travel slower and ALWAYS arrive after P-waves.
• S-waves travel like light waves in that they are “side to side” waves.
• S-waves only travel through Solids (S=S).
Locating an epicenter
This has to do with figuring out the difference in P-wave and S-wave arrival times. The closer (in minutes and seconds) they are together, the closer you are to the epicenter. Conversely, the farther the time between P-waves and S-waves, the farther you are located away from the epicenter.
Brain Teaser:
If they occur at the same exact time, where are you located???